Handout photoUndated handout image from the official House of Representatives site of Democratic U.S. Representative Gabrielle Giffords of Arizona.

TUCSON, Ariz. — Doctors said today that Arizona Rep. Gabrielle Giffords had given a thumbs up sign and tried to grab her breathing tube — heartening developments two days after surgery for a gunshot wound to the head.

Dr. Peter Rhee said surgeons had seen many encouraging signs. On Sunday and today, Giffords was able to respond to a verbal command by raising two fingers with her left hand.

"When she did that, we were having a party in there," Rhee said. And even while sedated, she has reached for her breathing tube. "That's a purposeful movement. That's a great thing. She's always grabbing for the tube," Rhee said.

Also, while her brain remains swollen, the pressure isn't increasing — a good sign for the congresswoman's recovery.

Neurosurgeon Dr. Michael Lemole of Tucson's University Medical Center said swelling from such an injury typically peaks around the third day, so doctors "can breathe a collective sigh of relief" once that point is reached on Tuesday.

In addition, Rhee said that two specialists from the Washington, D.C., area are being brought in. Col. Geoffrey Ling and Dr. James Ecklund have experience in treating combat wounds.

Of those injured in the deadly shooting Saturday in Tucson, eight are still hospitalized. Giffords is in critical condition, five are in serious condition, and two are in good condition.

Recovering from a gunshot wound to the head depends on the bullet's path, and while doctors are optimistic about Giffords' odds, it can take weeks to months to tell the damage.

Doctors say the bullet traveled the length of the left side of the Arizona congresswoman's brain, entering the back of the skull and exiting the front, above the left eye socket.

For now, her biggest threat is brain swelling. Surgeons removed half of her skull to give the tissues room to expand without additional bruising.

That bone is being preserved and can be re-implanted once the swelling abates, a technique the military uses with war injuries.

Giffords is being kept in a medically induced coma, deep sedation that rests her brain. It requires a ventilator so she cannot speak. It's too soon to know if she could speak if the ventilator were removed.

Doctors periodically lift her sedation to do tests, such as asking her to raise two fingers or squeeze someone's hand.